At least one victim from Ireland has been confirmed. Four people on board held a UN passport.

Ms Toole travelled a lot for work. Picture: Facebook

There were no Australians on board.

A British man has spoken about the final hours he spent with his dad, British and Kenyan dual citizen Joseph Waithaka, 55, who was also killed.

Mr Waithaka moved to the UK in 2004 and back to Kenya in 2015.

He had been visiting relatives in London on Saturday, before flying back to Addis Ababa, his son Ben Kuria told the BBC.

"I gave him a hug and shook his hand, because in my culture it's more about the handshake than it is about the hug," Mr Kuria said.

"And I said we'll probably see you at some point soon. We usually spend a bit more time saying goodbye, but yesterday it kind of just felt routine."

British Prime Minister Theresa May said she was "deeply saddened" to learn of the tragedy that claimed the lives of seven Brits.

"I was deeply saddened to hear of the devastating loss of life following the plane crash in Ethiopia," she said in a statement on Twitter.

"At this very difficult time my thoughts are with the families and friends of the British citizens on board and all those affected by this tragic incident."

UNITED NATIONS TO FLY FLAGS AT HALF-MAST

Married father of two Michel Ryan, from Ireland, has also been confirmed as a victim.

The Irish Times reports the man from County Clare worked with the UN World Food Programme as global deputy chief engineer.

Ireland's prime minister Leo Varadkar said Mr Ryan was "doing life-changing work in Africa with the World Food Programme" and expressed his sympathies to Mr Ryan's family, colleagues and friends.

Irish UN worker Michael Ryan was also killed. Picture: Facebook

As many as 19 United Nations workers died in the crash, the UN Department of Safety and Security in Kenya said.

That included workers with the Office of the High Commissioner on Refugees, World Bank, International Telecommunications Union, the UN Environment Program and others, according to AP.

German national Anne-Katrin Feigl, who worked with the UN migration agency, has also been confirmed as a victim.

The UN and its agencies will fly flags at half-mast today as a mark of respect.

A spokesman for the UN secretary-general, António Guterres, said he was "deeply saddened at the tragic loss of lives".

"He conveys his heartfelt sympathies and solidarity to the victims' families and loved ones, including those of United Nations staff members, as well as sincere condolences to the government and people of Ethiopia," the spokesman said.

"The United Nations is in contact with the Ethiopian authorities and working closely with them to establish the details of United Nations personnel who lost their lives in this tragedy."

More than 4700 officials have been gathering in Nairobi for the UN Environment Assembly from March 11 to 15.

As more heartbreaking stories from the crash emerge, Slovakian MP Anton Hrnko said his family had died in the crash.

"With deep sadness I announce that my dear wife Blanka, son Martin and daughter Michal died during the air disaster in Addis Ababa today in the morning hours," he wrote on Facebook.

The 36-year-old worked for the United Nations. Picture: Facebook

Ms Toole is the first of the British victims to be identified. Picture: Facebook